TEMPERATURE-PROGRAMMED DESORPTION AND CONVERSION OF ACETONE AND DIETHYL KETONE PREADSORBED ON HZSM-5
TEMPERATURE-PROGRAMMED DESORPTION AND CONVERSION OF ACETONE AND DIETHYL KETONE PREADSORBED ON HZSM-5
复制标题
DOI：
10.1016/s0144-2449(05)80062-4
复制
发表时间：
1991-11-01
期刊：
影响因子：
--
通讯作者：
NOVAKOVA, J
中科院分区：
文献类型：
--
作者：
KUBELKOVA, L;NOVAKOVA, J
用FTi. r研究了预吸附的丙酮、丙酮-d 6、二丙酮醇、异亚丙基丙酮和二乙基酮在HZSM-5上程序升温脱附过程中表面络合物的形成。谱通过质谱分析所产生的反应产物。结果表明，丙酮在低温下通过沸石桥连羟基转化为异亚丙基丙酮。异亚丙基丙酮在150- 250摄氏度之间进一步缩合和裂解，主要释放异丁烯到气相中，形成取代骨架OH基团的不饱和环状酮。这些新的表面酮是热稳定的，并作为催化毒物。二乙基酮不会形成类似的稳定表面络合物，主要通过分子内脱水反应生成释放到气相中的戊二烯。在丙酮和二乙基酮的转化过程中观察到的其他烃最有可能分别通过异丁烯和戊二烯的次级反应形成。
The formation of surface complexes during the temperature-programmed desorption, accompanied by conversion, of preadsorbed acetone, acetone-d6, diacetone alcohol, mesityl oxide, and diethyl ketone on HZSM-5 was studied using FTi.r. spectroscopy. The reaction products evolved were analyzed by mass spectrometry. It was shown that acetone is converted at low temperatures by zeolitic-bridging hydroxyls to mesityl oxide. Mesityl oxide undergoes further condensation and cracking between 150-degrees and 250-degrees-C, releasing mainly isobutene into the gaseous phase and forming unsaturated cyclic ketones that replace skeletal OH groups. These new surface ketones are thermally stable and act as catalytic poison. Diethyl ketone does not form analogous stable surface complexes and reacts predominantly via intramolecular dehydration to pentadiene that is released into the gaseous phase. Other hydrocarbons observed during the conversion of both acetone and diethyl ketone are most probably formed via the secondary reactions of isobutene and pentadiene, respectively.